---@class class
---@field initialize fun(...)
---@field new fun(...)
middleclass = {
    _VERSION     = 'middleclass v4.1.1',
    _DESCRIPTION = 'Object Orientation for Lua',
    _URL         = 'https://github.com/kikito/middleclass',
    _LICENSE     = [[
      MIT LICENSE
  
      Copyright (c) 2011 Enrique García Cota
  
      Permission is hereby granted, free of charge, to any person obtaining a
      copy of this software and associated documentation files (the
      "Software"), to deal in the Software without restriction, including
      without limitation the rights to use, copy, modify, merge, publish,
      distribute, sublicense, and/or sell copies of the Software, and to
      permit persons to whom the Software is furnished to do so, subject to
      the following conditions:
  
      The above copyright notice and this permission notice shall be included
      in all copies or substantial portions of the Software.
  
      THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
      OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
      MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
      IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
      CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
      TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
      SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    ]]
  }
  
  local function _createIndexWrapper(aClass, f)
    if f == nil then
      return aClass.__instanceDict
    elseif type(f) == "function" then
      return function(self, name)
        local value = aClass.__instanceDict[name]
  
        if value ~= nil then
          return value
        else
          return (f(self, name))
        end
      end
    else -- if  type(f) == "table" then
      return function(self, name)
        local value = aClass.__instanceDict[name]
  
        if value ~= nil then
          return value
        else
          return f[name]
        end
      end
    end
  end
  
  local function _propagateInstanceMethod(aClass, name, f)
    f = name == "__index" and _createIndexWrapper(aClass, f) or f
    aClass.__instanceDict[name] = f
  
    for subclass in pairs(aClass.subclasses) do
      if rawget(subclass.__declaredMethods, name) == nil then
        _propagateInstanceMethod(subclass, name, f)
      end
    end
  end
  
  local function _declareInstanceMethod(aClass, name, f)
    aClass.__declaredMethods[name] = f
  
    if f == nil and aClass.super then
      f = aClass.super.__instanceDict[name]
    end
  
    _propagateInstanceMethod(aClass, name, f)
  end
  
  local function _tostring(self) return "class " .. self.name end
  local function _call(self, ...) return self:new(...) end
  
  local function _createClass(name, super)
    local dict = {}
    dict.__index = dict
  
    local aClass = { name = name, super = super, static = {},
                     __instanceDict = dict, __declaredMethods = {},
                     subclasses = setmetatable({}, {__mode='k'})  }
  
    if super then
      setmetatable(aClass.static, {
        __index = function(_,k)
          local result = rawget(dict,k)
          if result == nil then
            return super.static[k]
          end
          return result
        end
      })
    else
      setmetatable(aClass.static, { __index = function(_,k) return rawget(dict,k) end })
    end
  
    setmetatable(aClass, { __index = aClass.static, __tostring = _tostring,
                           __call = _call, __newindex = _declareInstanceMethod })
  
    return aClass
  end
  
  local function _includeMixin(aClass, mixin)
    assert(type(mixin) == 'table', "mixin must be a table")
  
    for name,method in pairs(mixin) do
      if name ~= "included" and name ~= "static" then aClass[name] = method end
    end
  
    for name,method in pairs(mixin.static or {}) do
      aClass.static[name] = method
    end
  
    if type(mixin.included)=="function" then mixin:included(aClass) end
    return aClass
  end
  
  local DefaultMixin = {
    __tostring   = function(self) return "instance of " .. tostring(self.class) end,
  
    initialize   = function(self, ...) end,
  
    isInstanceOf = function(self, aClass)
      return type(aClass) == 'table'
         and type(self) == 'table'
         and (self.class == aClass
              or type(self.class) == 'table'
              and type(self.class.isSubclassOf) == 'function'
              and self.class:isSubclassOf(aClass))
    end,
  
    static = {
      allocate = function(self)
        assert(type(self) == 'table', "Make sure that you are using 'Class:allocate' instead of 'Class.allocate'")
        return setmetatable({ class = self }, self.__instanceDict)
      end,
  
      new = function(self, ...)
        assert(type(self) == 'table', "Make sure that you are using 'Class:new' instead of 'Class.new'")
        local instance = self:allocate()
        instance:initialize(...)
        return instance
      end,
  
      subclass = function(self, name)
        assert(type(self) == 'table', "Make sure that you are using 'Class:subclass' instead of 'Class.subclass'")
        assert(type(name) == "string", "You must provide a name(string) for your class")
  
        local subclass = _createClass(name, self)
  
        for methodName, f in pairs(self.__instanceDict) do
          if not (methodName == "__index" and type(f) == "table") then
            _propagateInstanceMethod(subclass, methodName, f)
          end
        end
        subclass.initialize = function(instance, ...) return self.initialize(instance, ...) end
  
        self.subclasses[subclass] = true
        self:subclassed(subclass)
  
        return subclass
      end,
  
      subclassed = function(self, other) end,
  
      isSubclassOf = function(self, other)
        return type(other)      == 'table' and
               type(self.super) == 'table' and
               ( self.super == other or self.super:isSubclassOf(other) )
      end,
  
      include = function(self, ...)
        assert(type(self) == 'table', "Make sure you that you are using 'Class:include' instead of 'Class.include'")
        for _,mixin in ipairs({...}) do _includeMixin(self, mixin) end
        return self
      end
    }
  }
  
  function middleclass.class(name, super)
    assert(type(name) == 'string', "A name (string) is needed for the new class")
    return super and super:subclass(name) or _includeMixin(_createClass(name), DefaultMixin)
  end
  
  setmetatable(middleclass, { __call = function(_, ...) return middleclass.class(...) end })
  

  return middleclass